Orthopedic surgery

Radiation Protection in Orthopaedics

Orthopaedic surgeons are increasingly using X ray based fluoroscopic techniques in the operation theatre or in the fluoroscopy room. Procedures such as kyphoplasty, vertebroplasty, deformity correction, pelvic fixation, intramedullary inter-locking nails and CT guided biopsies require radiation exposure. The overall use of radiation in procedures performed by orthopaedic surgeons is not as much as that used by interventional cardiologists. However, the lack of training in radiation protection among orthopaedic surgeons remains a problem.

No. The radiation doses delivered to patients in most orthopaedic procedures under normal conditions will not cause effects such as skin injury, infertility and cataract [deterministic effect]. The typical skin dose in most uro-radiological procedures is less than 1 Gy whereas the threshold for erythema is 2 Gy. However, carcinogenic and genetic effects [stochastic effects] cannot be ruled out, although the probability of such effects can be minimized and is usually small. The typical radiation dose values in terms of dose area product (DAP) are mostly in the range of 0.02 to 20 Gy.cm2. At this level of radiation exposure, probability of radiation effects is much smaller than the benefits that usually occur.

By keeping the X ray tube as far away from the patient as feasible, keeping the image receptor as close to the patient as possible, keeping the foot on the pedal only when essential, reducing the number of images acquired (runs), using the navigation system, collimating the X ray beam, using last image hold, using pulsed fluoroscopy, minimal use of magnification reducing exposure to radiosensitive organs such as the breast and reducing oblique views.

Optimization of protection requires that exposure of patients be the minimum necessary to achieve the required diagnostic and therapeutic objective of the interventional procedure [BSS]. By no means should dose reduction compromise clinical information and outcome. In diagnosis, if the dose is reduced below the minimum necessary, the adverse effects may result in reduced quality and extent of information.

Staff protection

There are radiation dose limits for staff recommended by the International Commission on Radiological Protection (ICRP) that most countries tend to adopt. Currently the level is 20 mSv/year (actually 100 mSv in 5 years - not to exceed 50 mSv in any one year). This dose limit is based on the calculation of radiation risk over a full working life from the age of 18 years to 65 years (47 years) at the rate of 20 mSv per year, amounting to 20x47= 0.94 Sv and resulting in an excess cancer risk of 1 in 1000. Most orthopaedic surgeons using radiation protection devices and tools will have a radiation dose below typically 2 mSv/year.

Very unlikely. Proper use of radiation protection tools and techniques can prevent deterministic effects such as cataract and can avoid any significant increase in probability of cancer risk for many years to cover the full professional life. To date, there have been no reports of radiation induced cataract among orthopaedic surgeons, however such reports do exist for interventional radiologists and cardiologists [VA; CI; VA1].

It is possible to achieve a smaller risk of radiation effects for a full professional life using the ALARA (as low as reasonably achievable) principle. There are situations where protection of patients poses a great challenge, but this is not so much the case for staff, where protection can be reasonably achieved.